Lumia 950 and supplimental devices. Bluetooth only?

Do keyboards, mouses, and even touchscreens on larger displays need to connect to the Lumia 950 via Bluetooth if you're using the dock with continuum. Essentially, does the dock accept input from other devices.

For example, I have an older 1st-gen Surface RT tablet. It has a snap-in keyboard, and it obviously has a touchscreen. So can I plug the Lumia 950 into it, bypass the old RT operating system and use the OS on the phone instead without connecting the keyboard via Bluetooth? Will the touchscreen register? Will the keyboard actually track? Or does every single pairing device have to run through the phone in some way in order for it to affect the OS displayed on the tablet, laptop, or desktop?

Essentially your phone projects the OS on a screen like a desktop PC would on a screen. So yes for all peripherals to work they need to be connected to the phone, either wireless through bluetooth or through the continuum dock. The phone can then project the OS to a screen either via miracast (wifi direct) or HDMI or displayport (via the continuum dock). The original Surface RT does not support miracast but does have a micro HDMI port. But this port (like laptop HDMI ports) likely is an out-going port only. You can link your phone with the Surface RT through bluetooth, but only to transfer files, not input. Therefore, you can't use the Surface RT screen to project on and can't use the Surface keyboard or touchscreen to control your phone.